The Present Invention generally relates to surface mount connectors and, more particularly, to a surface mount connector with improved anti-wicking characteristics.
A pair of connectors are often used to connect cables including a plurality of conductive wires to a circuit member such as a printed circuit board. A first type of cable connector is provided with a plurality of terminals configured to contact the conductive wires in the cable. A second type of connector is mounted on the circuit member and has terminals with solder tails, each being connected to a contact pad provided on the surface of the board via reflow soldering. During the reflow process whereby the solder tails are connected to the pads of the board, solder may wick onto the side surfaces of the terminals and contaminate the contact portion of the terminals. In order to avoid such solder wicking, a terminal has been proposed in which a channel or groove is formed on the surface thereof in order to reduce such solder wicking.
Referring to FIG. 15 (and Japanese Patent Application Laid-Open (Kokai) 6-13145), a terminal 851 of an integrated circuit socket is mounted by press-fitting such terminal into a press-fit groove 812 formed in base member 811. Terminal 851 is an integrally formed member having a substantially U-shape and includes a contact section 851a and a body section 851b separated from each other in the vertical direction of the base member 811. The body section 851b includes a fixed section 852 with one end connected to a coupling part of the contact section 851a, an angled section 853 connected to the other end of the fixed section, and a solder tail 854 connected to the angled section 853. Press-fit projections 855 are formed on both sides of the fixed section 852.
The distance b1 between the tips of the press-fit projections 855 is larger than the width b2 of first groove 813 in the press-fit groove 812 into which the fixed section 852 is press-fit. When the press-fit projections 855 engage the side surface of the first groove 813, they securely fix the terminal 851 to the base member 811. The width c1 of the angled section 853 is larger than the width c2 of second groove 814 in the press-fit groove 812. Thus, when the fixed section 852 is press-fit in the first groove 813, the angled section 853 is press-fit in the second groove 814 so as to further securely fix the terminal 851 to the base member 811.
A groove 851c configured to reduce solder wicking is formed in a portion located at a midpoint of the body section 851b. When solder wicks up the angled section 853 during soldering of solder tail 854 to the contact pad of a board (not shown), the solder is blocked by the groove 851c thus preventing further solder wicking.
However, in practice, the conventional terminal 851 might suffer from so-called flux-wicking where flux contained in the solder wicks up the side surface of the terminal 851 when the solder tail 854 is soldered to the contact pad on the surface of a board via reflow soldering. In the molten state, flux has a higher flowability than solder and therefore, formation of the groove 851c alone may prevent occurrence of solder-wicking but has difficulty in preventing the flux from wicking. If flux-wicking occurs and the flux contacts the contact section 851a, the contact section 851a may be sufficiently contaminated to prevent a reliable contact between contact section 851a and a counterpart terminal (not shown).